Seasonal energy storage is a tricky issue for our renewable future

Energy storage is a tricky issue.

It is fundamental to management of the grid as the proportion of “variable” renewable energy increases.

Its economics are sensitive to the gap between high and low prices, its “round trip” efficiency, and its capacity to capture income from value adding services that stabilise the grid during transient events.

But more investment in storage means less revenue for each storage operator. Developers of large pumped hydro schemes and advocates for renewable hydrogen recognise that it will be difficult to compete with batteries, smaller pumped hydro and demand response to capture value from short-duration peaks and troughs in demand.

Accordingly, they are focusing increasingly on supporting seasonal variation as their core role. Hydro operators and hydrogen producers want to capture excess low-priced seasonal renewable electricity, then generate during supply shortages when prices are higher.

In light of all this, the above graph from the AEMO’s recently published Integrated System Plan is significant. It maps out how a seasonal storage plant might operate.

However, it also highlights—again—that Australian energy policy makers and investors lack focus on the demand side of the energy equation.

It is mainly demand side factors that drive the need for autumn top-up, along with heavy drawdown in winter due to limited solar generation, and the need for storage to build up during the summer.

We must therefore ask what activities are contributing to high demand. What potential is there for energy efficiency to reduce the seasonal variation in demand, not just the short-term peaks?

AEMO’s graph highlights a number of possibilities. The major factors underlying seasonal variation are poorly performing buildings, and inefficient heating and cooling equipment.

These include thermally disastrous buildings (both residential and commercial), widespread use of resistive electric heating and inefficient air conditioners, inefficient lighting, open shop doors, heat loss from poorly insulated hot water tanks and pipes, unnecessary use of pool filter pumps, inefficient industrial processes and so on.

Addressing these would reduce seasonal variation, along with the need for the seasonal storage and seasonal hydrogen-sourced generation shown in AEMO’s graph.

This also means that there is a lot of risk for investors in such storage projects: indeed, governments may need to actively incentivise investment in seasonal storage to reduce investor risk.

But this raises another question: will such incentives end up creating uneconomic storage infrastructure, which will eventually be overtaken by demand-side transformation?

Information challenges

I often get requests for practical, numerical information on aspects of energy use by appliances, buildings and vehicles (among lots of other things).

It is becoming increasingly difficult to find quality data to underpin practical advice. The most recent detailed resource I found on school energy use at the activity level, for example, was dated 2013.

The last real-world government tests of new car fuel consumption were carried out prior to 2010.

Some community groups (including Renew) try to provide useful information, and while some resources such as Your Home are helpful, they are also woefully inadequate.

This is a serious problem, and governments need to invest in measurement, engagement and communication in user-friendly formats, so people and businesses can be empowered and make informed judgements.

My ten-year-old Australian Greenhouse Calculator, hosted by EPA Victoria, still seems to be the only comprehensive option for households to explore their emissions in any detail from the bottom up. It’s still available, but only until December.

This is because it relies on Adobe Flash, which is being phased out across the web. It works with Internet Explorer, and will also work if you actively allow Flash to run on other browsers such as Chrome. It would be great if funding was made available to update it!

For now, the tool is available for use here:apps.epa.vic.gov.au/AGC/home.html

This column was first published in Renew Magazine. Republished with permission of the author.